The present invention relates to tufting machines and more particularly to a tufting machine wherein the needles are selectively engageable and are carried in needle modules characterized by opposing pairs of needle holders which retain needles in an in-line, or linear arrangement.
Tufting machines which produce carpet typically include a large frame having a head within which a rotatable mainshaft is mounted and from which needle driving structure is supported for reciprocation of a multiplicity of needles. The frame also includes a bed within which oscillating loopers or hooks are mounted for cooperating with the needles to form loops of yarn, knives being used in conjunction with the hooks to cut the loops in many tufting machines.
As the tufting art has developed, there have been a substantial number of innovations to obtain unique patterning effects. One such innovation has been to shift the needles laterally in accordance with a pattern. Another innovation has been to provide each needle with a sew/no-sew capability by mounting the needles on individual needle holders which are reciprocated selectively by either being latched to or disengaged from a reciprocating latch bar, the latter being reciprocably driven continuously from mechanism driven by the rotating mainshaft. When latched to the latch bar, the needle reciprocates into cooperation with the hook to form a loop. The latching occurs by means of latch pins on pneumatic cylinders driven in accordance with a pattern. Machines of this type are known as controlled needle machines, and when each needle is individually controlled in this manner, it is known as an individually controlled needle machine.
A significant development in the tufting art was to combine the individual controlled needle machine concept with the shifting needle concept, and to feed the backing material intermittently. This provides a tufting machine wherein the needles may be threaded with a number of different yarns, e.g., yams of different colors, and a needle having a yarn of a particular color may be inserted into the backing at any of a selected number of locations so that precise multi-color patterns may be produced similar to the fine woven carpets produced by looms. A machine of this type is illustrated in Bardsley, U.S. Pat. No. 5,653,184.
Over the years, a number of improvements have been made to this design. Specifically, Bardsley, U.S. Pat. No. 5,974,991 provided an improvement to tufting machines to provide needle holders which are individually latched to a reciprocating drive bar and include externally mounted springs, each spring biasing a ratchet clamp which provides for sew/no-sew capability for respective needles
Other tufting machine designs apart from individually controlled needle machines have employed opposing pairs of needle holders including Bardsley, U.S. Pat. No. 4,790,252 and Price, U.S. Pat. No. 4,815,402. The ""252 patent allowed for only one, or the other, of the needle holders to be operated at by a particular push rod. This allowed for opposing needles to have different type yarns to create unique patterning effects. However, it was not possible to operate both pairs of opposing needle holders at the same time.
The ""402 patent discloses that opposing pairs of needles may be moved simultaneously, but does not teach the orientation of opposing pairs of needles in a single linear relationship. Furthermore, the ""402 patent does not contemplate opposing needle holders to be constructed in an easily replaceable needle module or modules.
Along with efforts to create unique patterning effects, an increase in detail has been desired. One way to increase the detail of the patterning effects is to decrease the gauge, i.e., the average distance between needle centerlines across the tufting machine. Although it appears that one would only need to reduce the diameter of the needles themselves and/or the thickness of the needle holders to decrease the gauge, this unfortunately weakens these components and increases their failure rate.
The ""402 patent teaches one way of decreasing the gauge of tufting machines, but improvements to this basic design are necessary in many applications. For instance, the ""402 patent contemplates two parallel and spaced apart rows of needles. The gauge on either of the two rows is half the gauge of the asserted gauge of the machine. The finer gauge is achieved as a result of staggered needles, not a single row of needles. While staggered needles may be satisfactory for some applications, tails of yarn formed by start up of needles in front row of needles are sewn through by rear needles. This is not desirable.
Consequently, it is a primary object of the present invention to provide a tufting machine having opposing needle modules providing a single row of needles arranged in a linear relationship.
It is another object of the invention to provide a needle module having two or more needle holders connected by guide plates to a mounting block adapted to be secured within a tufting machine.
It is a further object of the present invention to provide a needle module which supports two or more needle holders and a mounting block adapted to be secured within a tufting machine.
It is still a further object of the invention to provide a tufting machine with roughly half the gauge of adjacent needle holders.
Accordingly, the present invention provides a tufting machine having opposing sets of needle holders connected together in the form of needle modules. This configuration provides increased rigidity to the needle holders and is believed to speed the replacement of spent parts. The needle holders are preferably offset one from the other so that the gauge of the needle module may be half the gauge of either of the sets of opposing needle holders. Furthermore the needles from the opposing sets of needle holders are preferably arranged in a single linear relationship relative to one another.
Not only do needle holders gain stability from being connected to opposing needle holders, but the mounting block preferably connects the needle module to a post for lateral stability of the needle module. The connection to the post may allow for up and down adjustment of the needle module, while retaining the mounting block in a fixed position during operation of any of the individual needle holders.